Photoelectronic element includes many types, such as Light-emitting Diode (LED), solar cell, and photo diode. Taking LED for example, LED is a solid state semiconductor element comprising a p-n junction formed between a p type semiconductor layer and an n type semiconductor layer. When imposing a certain level of forward voltage to the p-n junction, holes from the p type semiconductor layer and electrons from the n type semiconductor layer are combined to release light. The region of releasing the light is generally called light-emitting region.
The features of LED mainly include small size, high efficiency, long life, quick reaction, high reliability, and fine color. So far, LED has been applied to electronic devices, vehicles, signboards, and traffic signs. Along with the launch of the full-color LED, LED has gradually replaced traditional lighting apparatus such as fluorescent lights and incandescent lamps.
Each of the foregoing photoelectronic elements can further connect a substrate thereof to a base via solders or adhesive elements. Moreover, the base includes at least a circuit to electrically connect with a contact of a light-emitting device or a light-absorbing device via a conductive structure such as wire lines.